Practice java Quizzes

Enhance your java skills with carefully curated quizzes designed to improve concept clarity and real-world application. Each question reinforces key principles through active practice. Ideal for students and professionals, these quizzes help you learn faster, stay sharp and strengthen your overall technical expertise.

Explore All java Quizzes

Learn java step by step with interactive quizzes designed for beginners and learners revising key concepts. Build a strong foundation with clear, structured practice in java.

Question 1

What is the maximum value that can be stored in a byte variable in Java?

255

127

32767

Question 2

Which data type is used to store a single character in Java?

int

char

string

Question 3

What is the default value of an int variable in Java if it's not explicitly initialized?

garbage value

null

Question 4

What will be the output of following Java Code?

public class Main {
    public static void main(String[] args) {
        int[] arr = new int[3];
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i]);
        }
    }
}

000

111

error

garbage value

0 0 0

Question 5

Which of the following is not a valid identifier for a Java variable?

3rdvar

_myvar

my_var

$var

Question 6

What is the size of a long variable in Java?

12 bytes

4 bytes

2 bytes

8 bytes

Question 7

What is the range of values that can be stored in a short variable in Java?

-128 to 127

-32,768 to 32,767

0 to 255

0 to 65,535

Question 8

Which of the following is a primitive data type in Java?

Boolean

String

char

Integer

Question 9

Which keyword is used to declare a variable that can hold a reference to an object of any class in Java?

object

class

var

genric

Question 10

What is the default value of a boolean variable in Java if it is not explicitly initialized?

null

false

true

Question 11

Which of the following is the correct way to declare a hexadecimal value in Java?

0x1A

#1A

0b1A

Question 12

What is the minimum value that can be stored in a char variable in Java?

-128

'a'

-32768

Question 13

Which of the following is not a primitive data type in Java?

char

byte

int

String

Question 14

What is the default value of a double variable in Java if it's not explicitly initialized?

null

1.0

garbage value

0.0

Question 15

What will be the output of following Java Code?

public class Main {
    public static void main(String[] args) {
        int myVar;
        System.out.print(myVar);
    }
}

compile time error

runtime error

garbage value

Question 16

What will be the output of following Java Code?

public class Main {
    static int myVar;
    public static void main(String[] args) {
        System.out.print(myVar);
    }
}

compile time error

runtime error

garbage value

Question 17

What will be the output of following Java Code?

public class Main {
    public static void main(String[] args) {
        static int myVar;
        System.out.print(myVar);
    }
}

garbage value

runtime error

compile time error

Question 18

What will be the output of following Java Code?

public class Main {
    int myVar;
    public static void main(String[] args) {
        Main obj = new Main();
        System.out.print(obj.myVar);
    }
}

garbage value

compile time error

runtime error

Question 19

What is the keyword used to declare a constant value in Java?

const

constant

final

static

Question 20

Which of the following is not a valid way to declare an integer variable in Java?

int x = 42.5;

int x = -42;

int x =42;

int x = 0x42;

Question 21

What is the default value of a char variable in Java if it's not explicitly initialized?

'\u0000'

null

'0'

Question 22

What will be the output of following Java Code?

public class Main {
    public static void main(String[] args) {
        char myVar;
        System.out.print(myVar);
    }
}

garbage value

runtime error

compile time error

Question 23

What will be the output of following Java Code?

public class Main {
    static char myVar;
    public static void main(String[] args) {
        System.out.print(myVar);
    }
}

compile time error

An empty space (because the default value of myVar is '\u0000')

null

Question 24

What will be the output of following Java Code?

public class Main {
    public static void main(String[] args) {
        static char myVar;
        System.out.print(myVar);
    }
}

garbage value

runtime error

compile time error

Question 25

What will be the output of following Java Code?

public class Main {
    char myVar;
    public static void main(String[] args) {
        Main obj = new Main();
        System.out.print(obj.myVar);
    }
}

An empty space (because the default value of myVar is '\u0000')

compile time error

null

Question 26

Which of the following is the correct way to declare a boolean variable named isJava and initialize it to true in Java?

bool isJava = true;

bool = true;

boolean = true;

boolean isJava = true;

Question 27

What is the size of a float variable in Java?

4 bytes

2 bytes

8 bytes

12 bytes

Question 28

What is the size of a double variable in Java?

12 bytes

2 bytes

4 bytes

8 bytes

Question 29

What is the range of values that can be stored in a char variable in Java?

-128 to 127

0 to 65535

-32768 to 32767

0 to 255

Question 30

What is the default value of a boolean array element in Java if it's not explicitly initialized?

false

null

true